The present relates to a grinding device for grinding an end face, especially an annular surface, at the edge of a workpiece bore with a driven grinding tool, the grinding surface of which extends angularly relative to the axis of a guide pin which for a precise introduction into the machined (for example, honed) bore has an identical size (identical dimensions) and which is connected to the grinding tool.
A known device of this kind is disclosed in German patent application 44 41 623 A1 and serves for fine machining a chamfer at the edge of a workpiece bore which serves as a sealing seat for a valve needle. Such valve bores are, for example, provided for injection pumps of combustion engines. They have a very small diameter of only a few millimeters and must be machined very precisely. The end face forming the edge of the bore and surrounding the bore of the workpiece must also be machined very precisely. For grinding or other surface machining of a chamfer, it must be taken into consideration that the truncated cone surface must be positioned exactly concentrically to the axis of the workpiece bore. The known device has a grinding tool with a conical grinding surface for the purpose of surface machining of the chamfer. The grinding tool with its grinding surface is driven so as rotate about the axis of the bore. The shape of the chamfer depends directly on the shape of the grinding surface of the grinding pad which in mass production must be frequently subjected to a trueing or dressing process. Since grinding pads or coatings are in general inhomogeneous, the shape precision and the surface quality of the chamfer in mass production is often unsatisfactory for high-precision workpieces.
Plane honing devices are also known in which the honing tool is displaced with its grinding coating or pad on the surface to be machined. These devices however can not be used for machining processes with limited available space because of their relatively large size.
It is therefore an object of the present invention to embody a device requiring only little space, i.e., space as small as possible, that can produce or machine small end faces, especially annular surfaces at the edge of a bore, with very high precision.